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I think you need to understand what a "tolerance" means in an assembly items. My token view is, a tolerance is the permissible deviation of a part from its ideal design dimension. Additionally, under the non-ideal situation, the assembly will not lose its intended functionality, and desired level of performance. After that, you may start to tighten ...


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There are general tolerances, often defined for different industries. You cannot expect that a surgical instrument is designed with the same general tolerances as a drilling rig. If you have found a norm for your industry, e.g. this ISO-standard, than there are still different classes of "tightness" you can choose from. Here should just check what ...


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If the request is coming from whoever will be machining or inspecting the part, I would side with them. They know what they need to see to make sure the part ultimately meets the print. Also, since your first datum is on the opposing face this implies it is getting machined first, hence why it is a reference datum. The geometry of the face you're making the ...


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Assuming the limitation is power/heat buildup... The power dissipated in the motor winding is a square function... if you decrease the voltage by 50% (and therefore the current) you have decreased the power by a factor of 4... down to 25% of its original value. Any motor rated to run for 25min "ON" time, and at 80% duty cycle, will surely have no ...


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Typically in my experience, your 3 orthogonal edges of the rectangular blank are your first 3 datums. Your dowel hole would be the first machined feature and since it locates the rest of the features, this would be your 4th datum. Your subsequent features would reference that 4th datum, as well as any of the original 3 to tolerance the features.


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If you use ASME Y14.5, typical implied tolerances are +/-: 1/64 for fractional dimensions 0.01 for dimensions to 2 decimal places 0.005 for dimensions to 3 decimal places 0.0005 for dimensions to 4 decimal places You just list all these and whatever other common requirements you have in your drawing block for the part. This way every feature is inherently ...


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This is a very difficult answer to answer within a single post but I'll give it a try. Tolerances, Cost and Machine capability The very first thing you need to remember is that tolerances are indirectly related to cost. More precisely, having tight tolerances means that two objects will be more closely matched compared to two others with looser tolerances. ...


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3rd edition Marks HandBook circa 1923 is what I use. When the local library re-opens, check out the modern versions in the reference section.


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There are standards. But that's really putting the cart before the horse. Imagine you're designing ..anything. By default the tolerance is whatever you can expect from the fabrication process if everything is done very poorly, and carelessly. Is the part still acceptable? If so then you're done, no tolerance needed (practically speaking). Most of the time ...


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To my experience yes, this Cover Your Ass usage is a relatively common, especially when you are outsourcing the machining and assembly. Actually, I've had an bad experience, at a company where I worked for. There was a particular order for solar trackers, that the CAD designer did not put in a welding specification, and somehow it was not spotted during ...


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I think you need something inline with this: Note that the datum A is identified by using an indicator under the callout. A-B could equally be used with the same meaning if you identify the two surfaces. You can have more explanation in ASME 14.5:2018 figure 6-6.


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This is fine, but not typical for cylindrical faces. The Profile GD&T symbol describes a 3D tolerance zone around the face, and as such is typically used for complex surfaces where other symbols cannot be used. See https://www.gdandtbasics.com/profile-of-a-surface


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